Generally, a system receives a stream of records and uses one or more rules to process each record independently of each other. As such, the rules only take the current record as input and output results for processing that record. When the system tests the rules, the testing is performed by applying one or more rules to a record, and the results of testing are shown only for that record. Usually, a software developer develops an application, which is then forwarded to a person testing the developed application. This may go back and forth several times until the approved application is released to the end-user. The end-user may have a request for a change of the application, and the end-user has to submit this request to the provider, who will then again involve the software developer and the testing person, who then tries to find a solution to incorporate the requested change. However, this may take several round-trips and does not allow at all that the end user performs any modifications.